Ferroelectric domain structures and temperature-misfit strain phase diagrams of K1-xNaxNbO3 thin films: A phase-field study

Wang, Bo; Chen, Hao Nan; Wang, Jianjun; Chen, Lei

doi:10.1063/1.5116910

Cited by 26 publications

(17 citation statements)

References 49 publications

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“…For local structures, the parameters were as follows: α 1 = 2.1 × 10 5 × (T-620) C −2 m 2 N, α 11 = −3.57 × 10 7 C −4 m 6 N, α 12 = 1.06 × 10 7 C −4 m 6 N, α 111 = 5.52 × 10 9 C −6 m 10 N, α 112 = 2.26 × 10 9 C −6 m 10 N and α 123 = 2.36 × 10 10 C −6 m 10 N, where only a cubic-orthorhombic phase transition can be found over the entire temperature range, and T is the temperature in Kelvin. The elastic constants and electrostrictive coefficients are supposed to be the same in the whole tetragonal ferroelectric structure and local structures: = 5.6 × 10 −12 m 2 N −1 , = −1.6 × 10 −12 m 2 N −1 , = 13.1 × 10 −12 m 2 N −1 , Q 11 = 0.166, Q 12 =−0.072, Q 44 = 0.042 48 – 50 . In the computer simulations, we used two-dimensional 128 × 128 discrete grid points and periodic boundary conditions.…”

Section: Methodsmentioning

confidence: 99%

The mechanism for the enhanced piezoelectricity in multi-elements doped (K,Na)NbO3 ceramics

et al. 2021

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Abstract(K,Na)NbO3 based ceramics are considered to be one of the most promising lead-free ferroelectrics replacing Pb(Zr,Ti)O3. Despite extensive studies over the last two decades, the mechanism for the enhanced piezoelectricity in multi-elements doped (K,Na)NbO3 ceramics has not been fully understood. Here, we combine temperature-dependent synchrotron x-ray diffraction and property measurements, atomic-scale scanning transmission electron microscopy, and first-principle and phase-field calculations to establish the dopant–structure–property relationship for multi-elements doped (K,Na)NbO3 ceramics. Our results indicate that the dopants induced tetragonal phase and the accompanying high-density nanoscale heterostructures with low-angle polar vectors are responsible for the high dielectric and piezoelectric properties. This work explains the mechanism of the high piezoelectricity recently achieved in (K,Na)NbO3 ceramics and provides guidance for the design of high-performance ferroelectric ceramics, which is expected to benefit numerous functional materials.

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Section: Methodsmentioning

confidence: 99%

The mechanism for the enhanced piezoelectricity in multi-elements doped (K,Na)NbO3 ceramics

et al. 2021

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“…Here, α denotes the Landau coefficients determined under the stress-free condition [ 28 ], σ i denotes the i th component of stress in Voigt notation, s 11 , s 12 , and s 44 denote the elastic compliance constants of a cubic phase [ 29 , 30 , 31 ], and Q 11 , Q 12 , and Q 44 denote the corresponding electrostrictive coefficients between polarization and stress [ 32 , 33 ].…”

Section: Methodsmentioning

confidence: 99%

Optimizing K0.5Na0.5NbO3 Single Crystal by Engineering Piezoelectric Anisotropy

Chen

Xie

et al. 2021

Nanomaterials

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K0.5Na0.5NbO3 is considered as one of the most promising lead-free piezoelectric ceramics in the field of wearable electronics because of its excellent piezoelectric properties and environmental friendliness. In this work, the temperature-dependent longitudinal piezoelectric coefficient d33* was investigated in K0.5Na0.5NbO3 single crystals via the Landau–Ginzburg–Devonshire theory. Results show that the piezoelectric anisotropy varies with the temperature and the maximum of d33max* deviates from the polar direction of the ferroelectric phase. In the tetragonal phase, d33maxt* parallels with cubic polarization direction near the tetragonal-cubic transition region, and then gradually switches toward the nonpolar direction with decreasing temperatures. The maximum of d33o* in the orthorhombic phase reveals a distinct varying trend in different crystal planes. As for the rhombohedral phase, slight fluctuation of the maximum of d33r* was observed and delivered a more stable temperature-dependent maximum d33maxr* and its corresponding angle θmax in comparison with tetragonal and orthorhombic phases. This work not only sheds some light on the temperature-dependent phase transitions, but also paves the way for the optimization of piezoelectric properties in piezoelectric materials and devices.

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“…Methods based on a higher scale generally require inputs from lower-scale methods (for example, density functional theory (DFT), constructs potentials that can be used for molecular dynamics (MD) simulations), and all methods necessitate inputs from model-aided characterization in order to construct realistic simulation supercells. Examples are in this sense, the use of effective Hamiltonians to calculate macroscopic properties (like phase transitions) in substituted BTO systems [ 249 ], the use of MD calculations to determine dynamic disorder in cubic BTO [ 250 ], and the use of phase-field modeling to capture ferroelectric domain structures and their dynamics [ 251 , 252 ]. With increased computational resources, it can be expected that these approaches will thrive in the next five to ten years, allowing researchers to bridge several length scales with integrated DFT-MD and phenomenological modeling approaches.…”

Section: Future Directionsmentioning

confidence: 99%

Strategies to Improve the Energy Storage Properties of Perovskite Lead-Free Relaxor Ferroelectrics: A Review

et al. 2020

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Electrical energy storage systems (EESSs) with high energy density and power density are essential for the effective miniaturization of future electronic devices. Among different EESSs available in the market, dielectric capacitors relying on swift electronic and ionic polarization-based mechanisms to store and deliver energy already demonstrate high power densities. However, different intrinsic and extrinsic contributions to energy dissipations prevent ceramic-based dielectric capacitors from reaching high recoverable energy density levels. Interestingly, relaxor ferroelectric-based dielectric capacitors, because of their low remnant polarization, show relatively high energy density and thus display great potential for applications requiring high energy density properties. In this study, some of the main strategies to improve the energy density properties of perovskite lead-free relaxor systems are reviewed, including (i) chemical modification at different crystallographic sites, (ii) chemical additives that do not target lattice sites, and (iii) novel processing approaches dedicated to bulk ceramics, thick and thin films, respectively. Recent advancements are summarized concerning the search for relaxor materials with superior energy density properties and the appropriate choice of both composition and processing routes to match various applications’ needs. Finally, future trends in computationally-aided materials design are presented.

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Ferroelectric domain structures and temperature-misfit strain phase diagrams of K1-xNaxNbO3 thin films: A phase-field study

Cited by 26 publications

References 49 publications

The mechanism for the enhanced piezoelectricity in multi-elements doped (K,Na)NbO3 ceramics

The mechanism for the enhanced piezoelectricity in multi-elements doped (K,Na)NbO3 ceramics

Optimizing K0.5Na0.5NbO3 Single Crystal by Engineering Piezoelectric Anisotropy

Strategies to Improve the Energy Storage Properties of Perovskite Lead-Free Relaxor Ferroelectrics: A Review

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